"thank-you-ma'am"

Everyday I get a word of the day sent to me in my email from Merriam Webster. Today I got this one and I thought it was really interesting, so I am sharing the wealth of knowledge.
Now it is your responsibilty to taked it and to use this word in your everyday life. I would be impressed.

thank-you-ma'am \THANK-yoo-mam\

noun : a bump or depression in a road; especially : a ridge or hollow made across a road on a hillside to cause water to run off

Example sentence: "That night on the way home, thinking of his pleasant visit, he was suddenly shaken out of his tranquility ... when his touring car hit a 'thank-you-ma'am' in the unpaved road." (Hugh Manchester, Centre Daily Times [State College, PA], August 22, 2000)

Did you know? "Thank-you-ma'am" might seem like an odd name for a bump in the road, but the expression makes a little more sense if you imagine the motion your head would make as you drove over such an obstacle. Most likely, the jarring would make you nod involuntarily. Now think of the nodding gesture you make when you're thanking someone or acknowledging a favor. The "thank-you-ma'am" road bump is believed to have received its name when someone noted the similarity of those two head bobbing motions. It's a colloquialism particular to American English, and its earliest printed use is found in Henry Wadsworth Longfellow's 1849 prose piece, Kavanagh: "We went like the wind over the hollows in the snow; — the driver called them 'thank-you-ma'ams,' because they make every body bow."